The present invention relates to a method and kit for typing feline blood. In particular, the present invention relates to a kit having a mixture of two monoclonal antibodies, which recognize feline specific A antigens on the feline erythrocytes.
Knowledge of feline blood group antigens is important to determine so as to eliminate adverse reactions that can occur after blood transfusions. In particular, before a cat can be given a blood transfusion, it is necessary to determine the cat""s blood type. If the wrong blood type is provided during a blood transfusion, a severe immune response may occur. Newborn kittens that nurse are also at risk because of naturally occurring anti-erythrocyte antibodies in the colostrum of some queens.
The consistent presence of naturally occurring antibodies to opposing blood types distinguishes cats from other major animal species in which this trait is absent or of minimal clinical significance. Of particular importance, most blood type B cats possess high titers of anti-A antibodies. These natural antibodies can result in severe haemolytic reactions to incompatible transfusions even on first administration. Neonatal isoerythrolysis and the related fading kitten syndrome are direct results of these potent anti-A antibodies. In contrast, only a small number of blood type A cats possess naturally occurring anti-B antibodies, and these are present in low titer. Blood type AB cats lack natural antibodies to either the A or B antigens.
Despite knowledge of the general organization and pattern of inheritance of the feline blood group system, it is still important to accurately blood type-subjects. This is especially true because in the rare AB blood type, the mode of inheritance is unknown. Of the three blood types, A, B, and AB, type A predominates in the more common Domestic shorthair/Domestic longhair (DSH/DLH) cats. Blood type B is much more likely to occur in certain breeds, particularly the Persian, Abyssinian, Birman, and related modern breeds, such as the Himalayan and British Shorthair. The AB blood type is by far the least common of the three and is characterized by the presence of both A and B antigens on the erythrocyte surface. Although blood type may be hypothesized with a fairly high degree of accuracy based on inherited characteristics, an individual""s blood type can only be hypothesized if the blood type of the parents is known. Further, a statistical estimate can only be made if the parents are of different blood types. It is essential to type a subject""s blood in order to determine the blood type. This is the only method to accurately determine the blood type.
Currently, feline anti-A antiserum harvested from type B cats is used as the typing reagent for detection of blood type A. To harvest the anti-A antiserum, a population of type B cats must be housed for a long time period. The cats must be periodically bled and the serum must be separated to use as the typing reagent. This process is problematic because the antibody titer, or concentration of antibody varies from one cat to another, introducing a variable that must be monitored between different batches of typing sera. Resultantly, these procedures can be costly. Also, the periodic bleeding of cats to harvest serum for blood typing purposes can be criticized or even prohibited by animal rights"" groups and governmental agencies in many parts of the world.
With the availability of rapid card tests, the practice of blood typing cats is utilized more routinely by veterinary practitioners than in the past. Current blood-typing products use anti-A antiserum from blood type B cats to detect type A and wheat germ lectin (WGL) to detect type B. As mentioned, feline anti-A antiserum can be expensive and labor-intensive to obtain. In addition, variability in source and preparation can affect its specificity and sensitivity. Therefore, it is desired to develop more specific and easily produced reagents for use in feline blood-typing. It is further desired to have a method that does not require cats to be housed and periodically bled.
The present invention relates to a method and kit for determining feline blood type. The present invention also relates to at least one isolated feline antibody, which binds to one or more receptors on an antigen that characterizes feline type A blood. Both the kit and method include the use of two different monoclonal antibodies, which recognize feline blood group specific A-antigens. One of the antibodies will recognize glycolipid A antigen (NeuGc)2GD3. The other antibody will recognize a second glycolipid A antigen other than (NeuGc)2GD3. Any monoclonal antibody may be used, as long as feline blood type A can be accurately recognized and the erythrocytes are agglutinated. In particular, the invention is used to determine whether a blood sample contains feline glycolipid A antigens.
The kit is formed by selecting a substrate member, such as a card, which facilitates contact between a mixture of the first and second monoclonal antibody with a blood sample. Use of a card is preferred; however, any system or device that allows the antibody mixture to be contacted with a blood sample may be used. Alternative testing systems include the use of a test tube. Optionally, an agent which agglutinates with blood type B may be included in the kit. The antibodies can be used in any of a variety of concentrations, as long as the blood visibly agglutinates. It is also preferred that the antibodies be mixed with other constituents, which inhibit the degradation of proteins. It is further preferred if the moisture in the antibody mixture is eliminated so as to preserve the proteins. One way to preserve the proteins is to lyophilize the mixture.
The method includes collecting a blood sample from a feline subject and contacting an amount of the sample with the antibody mixture. The sample may also be contacted with an agent which agglutinates blood type B. The antibody and sample mixture is then observed to see if the blood agglutinates with the anti-A antibody, and, optionally, the anti-B agent.
Any antibody can be used with the present invention, as long as it has a receptor for binding with feline type A blood. A preferred monoclonal antibody will have a receptor site for glycolipid A antigen (NeuGc)2GD3. A preferred second monoclonal antibody will have a receptor site for glycolipid A antigen that is similar to (NeuGc)GT3.
The present invention is advantageous because it provides for a quick and simple method for testing feline blood type. Additionally, the present method and kit alleviate the need to house a population of cats from which serum is harvested for use in blood typing. The present invention is also advantageous because it is more accurate than traditional testing methods. It is also more accurate than relying on known inheritance characteristics. Importantly, the present invention uses two separate monoclonal antibodies for determining blood type A.